CharacterMixer:
Rig-Aware Interpolation of 3D Characters

Xiao Zhan1, Rao Fu1, Daniel Ritchie1
1Brown University

Eurographics 2024

Teaser Figure

Abstract

We present CharacterMixer, a system for blending two rigged 3D characters with different mesh and skeleton topologies while maintaining a rig throughout interpolation. CharacterMixer also enables interpolation during motion for such characters, a novel feature. Interpolation is an important shape editing operation, but prior methods have limitations when applied to rigged characters: they either ignore the rig (making interpolated characters no longer posable) or use a fixed rig and mesh topology. To handle different mesh topologies, CharacterMixer uses a signed distance field (SDF) representation of character shapes, with one SDF per bone. To handle different skeleton topologies, it computes a hierarchical correspondence between source and target character skeletons and interpolates the SDFs of corresponding bones. This correspondence also allows the creation of a single "unified skeleton" for posing and animating interpolated characters. We show that CharacterMixer produces qualitatively better interpolation results than two state-of-the-art methods while preserving a rig throughout interpolation.

Paper • Code

Interpolation in rest pose

Interpolation during animation

Teaser Video

Citation

@article{https://doi.org/10.1111/cgf.15047,
    author = {Zhan, Xiao and Fu, Rao and Ritchie, Daniel},
    title = {CharacterMixer: Rig-Aware Interpolation of 3D Characters},
    journal = {Computer Graphics Forum},
    volume = {n/a},
    number = {n/a},
    pages = {e15047},
    keywords = {CCS Concepts, • Computing methodologies → Shape analysis, Shape modeling},
    doi = {https://doi.org/10.1111/cgf.15047},
    url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.15047},
    eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.15047},
}